An announcement of the decision is likely after the Prime Minister calls the CCPA meet on Sunday or Monday. The Tamil Nadu political parties and the Congress leaders from the state have been pressuring the PM not to visit to Colombo. They have been campaigning that the Sri Lankan President Mahinda Rajapaksa has violated all human rights during the war with LTTE and the Lankan government should be charged with war crimes.

The Sri Lankan High Commissioner to India Prasad Kariawasam had warned India that the nations which don't attend will be isolated. Some veteran diplomats feel that surrendering before the Tamil parties will actually harm India's standing in the Common Wealth.

But the Congress is scared of losing its alliance partner DMK (currently not a member of the UPA) in an all important election year. The Prime Minister has come under intense pressure over his visit to the island nation.

"The Prime Minister has a conscience, enough if acts according to his conscience. I did not threaten on withdrawing support. It's been long time since we withdrew our support," DMK chief Karunanidhi said.

Political parties and various groups in Tamil Nadu are strongly opposed to India's participation in the summit and the Tamil Nadu Assembly recently adopted a resolution demanding a complete boycott of the event alleging that Sri Lanka has indulged in atrocities against ethnic Tamils.